1. Field of the Invention
This invention relates to inspection apparatuses for printed boards (i.e., printed circuit boards or printed wiring boards), in which electrical inspection is performed on printed boards by bringing contact terminals into contact with contacts of printed boards.
This application claims priority on Japanese Patent Application No. 2003-8937, the content of which is incorporated herein by reference.
2. Description of the Related Art
Conventionally, inspection has been performed on printed boards having electrode patterns upon detection of electrical conduction established with wires or lines; that is, an inspection apparatus is operated so as to bring contact terminals thereof into contact with contacts arranged on each printed board, an example of which is disclosed in Japanese Patent Application Publication No. Hei 11-340588. Such an inspection apparatus has numerous contact terminals attached to a moving unit, wherein contact terminals are connected with one ends of wires, other ends of which are attached to a fixed unit and are connected to a measurement unit for measuring detection signals transmitted thereto from the contact terminals.
On the inspection surface of the printed board, electrode patterns are laminated onto an insulating film having a plurality of contacts, which are electrically conducted with the electrode patterns. A prescribed material having an ability to elastically deform such as copper, is used for the formation of electrode patterns. In an electrical conduction inspection, a printed board is fixed onto the upper surface of an inspection instrument, which is formed so as to be planar, while the moving unit is vertically lowered down to the printed board so that contact terminals are brought into contact with contacts of the printed board. In addition, the printed board is formed overall like a sheet in which a plurality of electrode patterns are formed, and the contact terminals are fixed to a probe head arranged in the moving unit.
The aforementioned inspection apparatus incurs relatively large costs in the creation of a probe head that is appropriately designed in shape and size to match the entire surface of a printed board to be inspected. For this reason, when an inspection is performed on a printed board in which a plurality of units of electrode patterns are formed, a so-called step-and-repeat method is performed using an inspection probe head matching one of the units of electrode patterns paired electrode patterns so that the electrode patterns are respectively inspected in turn. Even though this method is used, the measurement unit accompanied with the fixed unit is connected with numerous wires, the number of which is identical to the number of contact terminals. Therefore, the conventional inspection apparatus has a drawback in that the wiring becomes bulky due to the numerous wires required between the moving unit and the fixed unit.